Belt sander



Dec. 18, 1945. LUNDQUIST I 2,391,322

' BELT SANDER,

Filed Oct. 30, 1945 2 Sheets-Sheet 1 H. T Lund7zzj5z Dec. 18, 1945.

H. T. LUNDQUIST BELT SANDER FiledOct. so, 1943 ,2 Sheets-Sheet '2 Patented Dec. 18, 1945 UNITED STATE s- PAT1:15:15 OFFICE. I

:BELT SANDER 1 I Hjalmar f1. Lundquist, Kennett Square, Pa. Application October 30, 1943, Serial No. 508,322

,8 Claims. (01. 515-135;

This invention relates to grinding machines,

and more particularly to an endless belt type of sanding machine by means of which objects of variable shape can be rapidly and efiiciently sanded or ground. 7 H

The object of the present invention is to provide an improved and simplified sanding machine of the endless belt type, having increased flexibility coupled with provisions for. maintaining uniform abrasive pressure throughout the grinding surfaces.

The invention consists in the-novel construction, arrangement and combinations; of parts hereinafter more particularly described and claimed. a r

Two sheetsof drawings accompany this specification as part thereof, in which like reference characters indicate like parts throughout.

Figure 1 is a front elevation of the improved device with the front frame cover removed. a v

Figure 2 is a vertical medial crosssection. I

Figure 3 is a horizontal cross-section taken on line 3-3 of Figure l. r I

Figure 4 is a horizontal cross-section taken on line 4-4 of Figure 1.

Figure 5 is a horizontal cross-section taken on line 5-5 of Figure 1.

Figure 6 is a horizontal cross-section taken on line 6-6 of Figure 1.

Figure 7 is a vertical cross-section through the belt supporting assembly.

' Figure 8 is a fragmentary side elevation of the belt supporting assembly.

In accordance with the present invention, a back frame member I of substantially rectangular, form is provided having a medial trough-like notch 2 formed in its upper edge and having a peripheral flange 3 upon which is adapted to seat a cover 4 having in its upper face a similar notch vcomplementary to the notch 2, the two frame parts I and 4 constituting a housing for the grinding mechanism hereinafter described.

. Mounted upon the back I are a plurality of stub shafts arranged in pairs, the uppermost pair of shafts 6-6 being horizontally spaced so that one of these shafts is positioned on either side of the medial notch 2. Below these stub shafts are positioned another pair of shafts 8-8. Upon the shafts 6-6 are rotatably mounted multiple sheave pulleys 'I-I arranged so that the sheaves are staggered, one with respect to the other, as

illustrated in Figure 3, while on shafts 8-8 are rotatably mounted multiple sheave pulleys 9-9 staggered in the opposite direction as illustrated in Figure 4. r

l are suspended rotatably the weights Below this assembly of freely rotatable pulleys are arranged a pair of multiple sheave pulleys l3 fixedly'secured to shafts I2' journaled in back frame member 'I and suitably connected as by couplings II-II, with motors or other driving means III-I0 mounted on the back of frame member I. V

'An endless belt I! is carried in the sheaves of the pulleys I, 9 and I3 having the final reach extending around a single sheave pulley I4 mounted upon a shaft I5 on the ends of which Iii-I6 adapted to exert a uniform pressure upon the belt I! and 'adjust itself-angularly with respect to the front groove in pulley I3 and the rear groove of pulley 1.

The'outer face of the belt I! is provided with a suitable abrasive material and by the arrangement thus far described it will be apparent, by reference to Figure 1, that similar reaches ofthe belt' II will cross each other medially of the notches-1 in-the frame structure, providing a work-receiving trough 26 formed by angularly disposed stretches of the abrasive belt.

Supporting means for these trough-forming stretches of the abrasive belt is provided by a member I8 supported from the back I as by bolt 30, the member I8 being provided, as illustrated in Figure 7, with oppositely disposed cutaway portions through which extend shafts I9 upon which are pivotally mounted arms 20 extending alternately from one "side shaft I9 and the other to correspond with the reaches of the belt I1. Each of these arms 20 is provided near its free end with a lanar face 22 adapted to contact and support a reach of the belt I! adjacent the line of intersection of the portions of the belt constituting the work trough 26. The arms 20 on each shaft l9 are spaced by spacer rings 2|, each provided with a radially disposed rod 24, the free end of which fits slidably in a hole '23 provided in the rear edge of the oppositely disposed arm 20. Compression springs 25 surrounding rods 24 objects of straight or irregular contour can be effectively sanded. It will also be observed that regardless of the shape of the object sanded, the

ship to provide space between them for a work receiving trough, a single sheave pulley having'a depending weight, and an endless belt havingone face provided with an abrasive surface, said belt supported on said multiple sheave pulleys and carrying the weighted single sheave pulley,'-to form the intersecting walls of the work receiving trough said portions of the belt forming said trough walls all moving toward the line of intersection.

2. Sander comprising a housing including :a

'back frame member, a plurality of stub shafts trough having angularly disposed sides, the reaches of belt constituting each side of said trough traveling in the same direction and the freely suspended pulley being of a diameter to direct the belt from a pulley at one end of said trough to a pulley at the opposite end of said trough,

4. Sander comprising a frame, a plurality of pulleys mounted thereon, an endless belt positioned on said pulleys having-its outer face provided with an abrasive surface, said pulleys including driving pulleys and a belt supported tightening pulley arranged to direct said belt into a mounted onJthe back within the housing, aplu- 25 pulleyand an endless belt having its outer face rality of multiple sheave pulleys mounted on said shafts, two of said pulleys arranged :in spaced relationship to provide space between them for a work-receiving trough, an endless belt having an abrasive-coated outer face supported on said pulleys to intersect to form the walls of the work? receiving trough with all reaches of the belt constituting said trough arranged to move toward the line of intersection, the housing and back frame member notched to conform with said work-receiving trough. v

3. Sander comprising a frame, a plurality of pulleys mounted thereon including a driving pulley and a freely suspended weighted pulley and an endless belt positioned on said pulleys tr ough.

plurality of reaches constituting a work trough having angularly disposed sides, all reaches constituting each side of said trough traveling in the same direction, and the reaches of both sides traveling in converging directions, the belt tightening pulley of a suitable diameter to direct the belt from a pulley groove at one end of said trough to the pulley grooveat .theopposite end of said ,5. Sander comprising .a frame, .a plurality of pulleys mounted thereon including a driving provided with an abrasive surfacesaid belt arranged on said pulleys and said pulleys so arranged .as to presents, pluralityof reaches of said belt forming a work trough the sides l of which converge, said sides each formed by reaches of said belt and all of said :side forming-reaches of said belt arranged to travel toward the bottom of the trough, V a a v I 6. The device of claim 5 with means for maintaining said belt under tension.

7 The device-of claim 5-with means for supporting the trough forming reaches of the belt. 8. The device of claim 5 with independent means for resiliently supporting each of the trough forming reaches of the belt.

' HJALMAR T. LUNDQUIST. 

